Update Update: This morning/afternoon, I put the two extra coats of primer on the fenders, chain guard, and fork and also primed the frame. I went ahead and put 5 coats of primer on the frame, well-spaced at about 15 minutes between coats. I didn't get a real smooth coverage on the whole frame, not sure what the problem was. I'm hoping that buffing with the steel wool will smooth it out. I'm going to let everything dry again for at least 24 hours before I start with the paint.
I forgot to take a picture of the primed frame, but imagine this: it's all gray.
So, last night I used some "0000" steel wool to smooth out the primer before doing the first paint coat, and even a very light touch completely removed the primer in a few places on the fenders. I'm going to do another two coats of primer on everything; that's five coats altogether, if you're keeping track.
I'll post another update once I've done that.